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Finding the Fourth Proportional to 85.42, 117.78 and 54.30

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Solution

The fourth proportional to 85.42, 117.78 and 54.30 is: 74.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.42 : 117.78 = 54.30 : x
  2. Step 2: Convert to fraction form
    85.42/117.78 = 54.30/x
  3. Step 3: Cross multiply
    85.42x = 117.78 × 54.30
  4. Step 4: Simplify right side
    85.42x = 6,395.45
  5. Step 5: Solve for x
    x = 6,395.45/85.42
  6. Step 6: Final answer
    x = 74.87

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.